Arrowhead Pharmaceuticals Closes Underwritten Public Offering with Gross Proceeds of $60.4 Million

PASADENA, Calif.--(BUSINESS WIRE)--
Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) today announced that on
January 22, 2018 it closed the previously announced underwritten public
offering of 11,500,000 shares of its common stock, which included shares
issued upon the exercise in full by the underwriters of their option to
purchase 1,500,000 additional shares. The offering was priced at $5.25
per share, and the company received gross proceeds of approximately
$60.4 million, before deducting underwriting discounts, commissions and
other offering expenses payable by the company. Jefferies LLC and
Barclays Capital Inc. acted as bookrunning managers for the offering,
Cantor Fitzgerald & Co. acted as passive joint bookrunner for the
offering and Chardan and B. Riley FBR, Inc. acted as co-managers for the
offering.

About Arrowhead Pharmaceuticals

Arrowhead Pharmaceuticals develops medicines that treat intractable
diseases by silencing the genes that cause them. Using a broad portfolio
of RNA chemistries and efficient modes of delivery, Arrowhead therapies
trigger the RNA interference mechanism to induce rapid, deep, and
durable knockdown of target genes. RNA interference, or RNAi, is a
mechanism present in living cells that inhibits the expression of a
specific gene, thereby affecting the production of a specific protein.
Arrowhead's RNAi-based therapeutics leverage this natural pathway of
gene silencing.

This news release contains forward-looking statements within the
meaning of the "safe harbor" provisions of the Private Securities
Litigation Reform Act of 1995. Such forward-looking statements include
statements regarding our expectations with respect to our proposed
public offering. These statements are based upon our current
expectations and speak only as of the date hereof.Our actual
results may differ materially and adversely from those expressed in any
forward-looking statements as a result of various factors and
uncertainties, including, without limitation, risks and uncertainties
associated with market conditions and the satisfaction of customary
closing conditions related to the proposed offering.Our Annual
Report on Form 10-K, recent and forthcoming Quarterly Reports on Form
10-Q, recent Current Reports on Forms 8-K, and other SEC filings discuss
some of the important risk factors that may affect our ability to
achieve the anticipated results, as well as our business, results of
operations and financial condition. Readers are cautioned not to place
undue reliance on these forward-looking statements.Additionally,
Arrowhead disclaims any intent to update these forward-looking
statements to reflect subsequent developments.